Electric trains can't. Modern trolleybuses have auxiliary power units and can go short distances away from the wires. Given a comprehensive wire network within a city, trolleybuses can go pretty much anywhere in that city. This actually allows depots, especially on newer systems, to be unwired. Yet new trams are often supplied without them, with depots being wired even on new systems.

Electric or solar powered 'buses' could presumably replace the diesel and CNG buses at some point in the future. There is no need for millions of dollars to be spent electrifying the roads of Adelaide for this sole purpose.

Because if you're going to go to that length then may as well have a tram instead.

As much as it pains me to say this because I love the tangle of the overhead wires, but with modern technology we are steadily moving away from a need to have overhead. Sydney's new tram extension is an example of that.

Cheers, Mitchell Heard

South Australian Regional Rail Alliancewww.facebook.com/SARegionalRailAlliance

Since electricity is conveyed directly to them while in use, be careful about comparing them to electric buses that are charged while stationary. Battery powered buses are charged while out of service.

Consider this comparison, diesel bus, trolleybus, diesel train and straight electric train. Compare the difference between a diesel bus and a trolleybus to the difference between an electric train and a diesel train, and/or between a diesel bus and train and a trolleybus and straight electric train.

Heardy_101 wrote:As much as it pains me to say this because I love the tangle of the overhead wires, but with modern technology we are steadily moving away from a need to have overhead. Sydney's new tram extension is an example of that.

Sydney's new tram extension still has a power supply along the track, but at ground level. Its not a case of on-board storage supplying on-board loads.

In cities that still have trams, there are no plans for complete tram abandonment and trams are making a comeback in many places. But trolleybuses are not and there have been some trolleybus abandonment lately, Wellington being one of them. Why the double standard? If straight electric trams are making a comeback, why shouldn't trolleybuses?

actually trolleybuses and trams can travel without wires, provided by battery backup or 3rd undercover railLyon France has one of the modern trolleybus fleets in Europe and can travel without wires with battery back up. Trams in Bordeaux and Reims France travel through the city and historic centres without wires provided by a covered third rail. Makes me laugh when I see the cobweb of wires at the North Terrace/King William Street intersection and also could have been used in Jetty Road Glenelg

All new trolleybuses have battery packs for off-wire maneuvers. Batteries do indeed require recharging at regular intervals. For that matter, fuel tanks also require refilling at regular intervals. But fuel tanks can only be refilled at bus depots or dedicated service stations. Bus stops served by battery electric buses can be fitted with charging facilities and battery electric buses can charge at these, without having to go back to the depot to recharge. Or even better, the battery packs of trolleybuses charge up while on the move, and don't discharge until the bus moves away from the wires. That makes them an auxiliary power unit. Also, overhead wires (for trolleybuses as well as trams) can in fact be supported from buildings in some places.

Last edited by Myrtone on Sat Mar 17, 2018 7:03 am, edited 1 time in total.

Myrtone wrote:All new trolleybuses have battery packs for off-wire maneuvers. Batteries do indeed require recharging at regular intervals. For that matter, fuel tanks also require refilling at regular intervals. But fuel tanks can only be refilled at bus depots or dedicated service stations. Bus stops served by battery electric buses can be fitted with charging facilities and battery electric buses can charge at these, without having to go back to the depot to recharge. Or even better, the battery packs of trolleybuses charge up while on the move, and don't discharge until the bus move away from the wires. That makes them an auxiliary power unit. Also, overhead wires (for trolleybuses as well as trams) can in fact be supported from buildings in some places.

What? Refilling fuel tanks takes only a few minutes for several hours of use. Charging batteries can take longer than the use you get out of them. Rarely better than a 1:4 ratio.

Off wire maneuvers are useful sometimes but I'd wonder how feasible re-attaching trolleypoles in service actually is. Can the delay caused be less than a minute?

I know batteries take longer to charge, and one can get less use out of them per duty cycle, the fact is that batteries of trolleybuses can be charged while on the move, and the only use out of them is when going off wires. I know refilling fuel tanks takes quite a short time, but they can't be refilled while on the move, only at depots or service stations. This makes the range of a fuel tank more important, a full tank of a liquid or gaseous fuel must be able to take the bus as far as it will go on an entire shift. A battery weighing the same as a full tank of fuel has much less range and takes longer to charge but one on a trolleybus only needs enough range for off-wire maneuvers, specifically because it can be charged while on the move and stay charged until the bus needs to move away from the wires.

simonl wrote:What? Refilling fuel tanks takes only a few minutes for several hours of use. Charging batteries can take longer than the use you get out of them. Rarely better than a 1:4 ratio.

Off wire maneuvers are useful sometimes but I'd wonder how feasible re-attaching trolleypoles in service actually is. Can the delay caused be less than a minute?

Modern trolleypoles are controlled remotely from the driver's seat. Lowering poles can be done on the move and raising them is typically done at a bus stop during the time of the stop dwell, typically about 15 seconds or so.

Electric bus technology is in a state of rapid development at the moment and the trolleybus and battery bus are morphing with each other. There is no such thing as a traditional "pure" trolleybus on the new bus market today and "trolleybuses" are increasingly dynamic electric buses that run a significant part of the routes off-wire and recharge their batteries on the move on-wire. This is the way things are heading in the future lead-up to phasing out diesel buses. In the future, the only static recharge will be at the depot overnight when most buses are out of service anyway.

So there is no longer a debate about "should we convert our system to trolleybuses?" This has turned into the task of addressing the certainty that diesel city commuter buses will be replaced by electric buses over the next couple of decades. The issue is now which method to extract the maximum range from an electric bus without disruptive downtime and without compromising the internal functionality (passenger space) of the bus.

The trend is towards enabling the bus to run an entire roster without having to stop for recharge (except the overnight one at the depot), which means all these flash recharge technologies that tie the bus up for a fixed period of time at stops and termini will end up in the dustbin of history and the emphasis will be on topping the bus up on the move where necessary (dynamic charging). It looks like ground induction systems are turning out to be expensive and impractical and it may well be that the length of overhead wire at termini and along parts of routes will be the best solution.

tonyp wrote:Modern trolleypoles are controlled remotely from the driver's seat. Lowering poles can be done on the move and raising them is typically done at a bus stop during the time of the stop dwell, typically about 15 seconds or so.

I was going to note that.

tonyp wrote:Electric bus technology is in a state of rapid development at the moment and the trolleybus and battery bus are morphing with each other. There is no such thing as a traditional "pure" trolleybus on the new bus market today and "trolleybuses" are increasingly dynamic electric buses that run a significant part of the routes off-wire and recharge their batteries on the move on-wire. This is the way things are heading in the future lead-up to phasing out diesel buses. In the future, the only static recharge will be at the depot overnight when most buses are out of service anyway.

But there are plenty of fully electric buses on the market, and this includes trolleybuses. Trolleybuses without auxiliary power units have been withdrawn from the market because they are limited to their wires. In order to have the flexibility of, say, diesel or C.N.G buses, they do need batteries (and these do have a lower calorific value than even natural gas) but the minimum needed off-wire range is only a fraction of the minimum distance an internal combustion engined bus needs to be able to go between refuelings.

tonyp wrote:So there is no longer a debate about "should we convert our system to trolleybuses?" This has turned into the task of addressing the certainty that diesel city commuter buses will be replaced by electric buses over the next couple of decades. The issue is now which method to extract the maximum range from an electric bus without disruptive downtime and without compromising the internal functionality (passenger space) of the bus.

Trolleybuses may be the best way to go, but I don't get this.

tonyp wrote:The trend is towards enabling the bus to run an entire roster without having to stop for recharge (except the overnight one at the depot), which means all these flash recharge technologies that tie the bus up for a fixed period of time at stops and termini will end up in the dustbin of history and the emphasis will be on topping the bus up on the move where necessary (dynamic charging). It looks like ground induction systems are turning out to be expensive and impractical and it may well be that the length of overhead wire at termini and along parts of routes will be the best solution.

The idea of enabling a bus to run an entire roster on one battery duty cycle is basically treating electricity like a fuel, and batteries like fuel tanks. Traditionally, trolleybus wiring was placed along the entire length of the routes. With this approach, the auxiliary batteries would only discharge during temporary diversions, mainly when a stretch of road along a route is being rebuilt or repaired, these being quite short.

Heardy_101 wrote:Until Wellington recently closed their system, Wellington had recently upgraded overhead as well as fairly modern vehicles.

I was surprised by the decision to abandon them, not just given the recent purchase of new vehicles but also the trend back to trams, mostly powered in the same way.